Das ist es im wesentlichen.--++--When you think of it, it is quite easy, actually.First step: Determine the shape by drawing it. Then paint the dark areas and schadow either violet or green (decide by observation, if your´e interested in realism).Second step: Fill the shape with a skin-tone. The previously painted areas as well. But make it translucent where appropiate and opaque where appropiate (watch it closly!!).Third step: Mix a lighter skin-tone and highlight the parts necessary to give it volume (again: watch it closly!!).